U.S. patent application number 14/585823 was filed with the patent office on 2016-02-25 for assignment of wavelengths to optical signals in an optical network.
The applicant listed for this patent is Infinera Corporation. Invention is credited to Nitin K. GOEL, Steven Joseph HAND, Sudhindra Aithal KOTA, Marco E. SOSA, Onur TURKCU.
Application Number | 20160057519 14/585823 |
Document ID | / |
Family ID | 55349456 |
Filed Date | 2016-02-25 |
United States Patent
Application |
20160057519 |
Kind Code |
A1 |
HAND; Steven Joseph ; et
al. |
February 25, 2016 |
ASSIGNMENT OF WAVELENGTHS TO OPTICAL SIGNALS IN AN OPTICAL
NETWORK
Abstract
A method may include determining, by a device, a wavelength
identifier graph corresponding to an optical network based on a set
of lightpath conflicts, for a set of optical signals, associated
with a set of links and a set of nodes of the optical network. One
or more optical signals may be associated with transmission via a
super-channel. The method may further include selectively
assigning, by the device, a wavelength identifier to an optical
signal, of the set of optical signals, based on the wavelength
identifier graph. The wavelength identifier being associated with a
set of wavelength identifiers and corresponding to a wavelength of
a set of wavelengths. The method may further include causing, by
the device, the optical signal to utilize the wavelength, of the
set of wavelengths, for transmission via the optical network.
Inventors: |
HAND; Steven Joseph; (Los
Gatos, CA) ; TURKCU; Onur; (Santa Clara, CA) ;
KOTA; Sudhindra Aithal; (Bangalore, IN) ; GOEL; Nitin
K.; (Bangalore, IN) ; SOSA; Marco E.; (San
Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Infinera Corporation |
Sunnyvale |
CA |
US |
|
|
Family ID: |
55349456 |
Appl. No.: |
14/585823 |
Filed: |
December 30, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62041325 |
Aug 25, 2014 |
|
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|
Current U.S.
Class: |
398/49 |
Current CPC
Class: |
H04J 14/0241 20130101;
H04J 14/0212 20130101; H04L 45/62 20130101; H04Q 2011/009 20130101;
H04L 45/02 20130101; H04Q 2011/0086 20130101; H04Q 11/0066
20130101; H04J 14/0257 20130101 |
International
Class: |
H04Q 11/00 20060101
H04Q011/00; H04L 12/751 20060101 H04L012/751; H04J 14/02 20060101
H04J014/02 |
Claims
1. An apparatus, comprising: one or more processors configured to:
determine a set of optical signals associated with an optical
network including a set of optical links and a set of optical
nodes; determine topology information for the set of optical
signals and the optical network, the topology information including
information identifying a particular set of lightpath conflicts,
the particular set of lightpath conflicts including a first set of
lightpath conflicts associated with the set of optical links and a
second set of lightpath conflicts associated with the set of
optical nodes, the topology information corresponding to a
wavelength identifier graph, the wavelength identifier graph
including a set of vertices corresponding to the set of optical
signals and a set of edges corresponding to the first set of
lightpath conflicts and the second set of lightpath conflicts;
select an optical signal, from the set of optical signals, based on
the wavelength identifier graph; selectively assign a wavelength
identifier, of a set of wavelength identifiers, to the optical
signal based on the wavelength identifier graph, the wavelength
identifier, of the set of wavelength identifiers, corresponding to
a wavelength of a set of wavelengths; and cause the optical signal
to utilize the wavelength, of the set of wavelengths, for
transmission via one or more super-channels of the optical
network.
2. The apparatus of claim 1, where the one or more processors are
further configured to: determine a saturation degree of the optical
signal, the saturation degree being determined based on a quantity
of wavelength identifiers, of the set of wavelength identifiers,
associated with neighboring vertices to a particular vertex
corresponding to the optical signal; and where the one or more
processors, when selecting the optical signal based on the
wavelength identifier graph, are further to: select the optical
signal from the set of optical signals based on the saturation
degree of the optical signal.
3. The apparatus of claim 1, where the one or more processors are
further configured to: determine a degree of a vertex corresponding
to the optical signal, the degree of the vertex being determined
based on a quantity of edges, of the set of edges, associated with
the vertex corresponding to the optical signal; and where the one
or more processors, when selecting the optical signal based on the
wavelength identifier graph, are further to: select the optical
signal from the set of optical signals based on the degree of the
vertex corresponding to the optical signal.
4. The apparatus of claim 1, where the one or more processors are
further configured to: determine a quantity of unassigned neighbors
of a vertex, of the set of vertices, corresponding to the optical
signal, the quantity of unassigned neighbors being other vertices,
of the set of vertices, that neighbor the vertex and have not been
assigned a particular wavelength identifier, of the set of
wavelength identifiers, corresponding to a particular wavelength;
and where the one or more processors, when selecting the optical
signal based on the wavelength identifier graph, are further to:
select the optical signal from the set of optical signals based on
the quantity of unassigned neighbors.
5. The apparatus of claim 1, where the one or more processors, when
selectively assigning the wavelength identifier, are further
configured to: select a particular wavelength identifier, of the
set of wavelength identifiers, to assign to the optical signal;
determine that the particular wavelength identifier, of the set of
wavelength identifiers, is not tunable by a transmitter associated
with the optical signal; and select another wavelength identifier,
of the set of wavelength identifiers, to assign to the optical
signal based on the wavelength identifier graph.
6. The apparatus of claim 1, where the one or more processors, when
selectively assigning the wavelength identifier, are further
configured to: select a particular wavelength identifier, of the
set of wavelength identifiers, to assign to the optical signal;
determine that the particular wavelength identifier, of the set of
wavelength identifiers, is not tunable by a receiver associated
with the optical signal; and select another wavelength identifier,
of the set of wavelength identifiers, to assign to the optical
signal based on the wavelength identifier graph.
7. The apparatus of claim 1, where the one or more processors, when
selectively assigning the wavelength identifier, are further
configured to: select a particular wavelength identifier, of the
set of wavelength identifiers, to assign to the optical signal;
determine that the optical signal is not routable based on
selecting the particular wavelength identifier; and select, based
on determining that the optical signal is not routable, another
wavelength identifier, of the set of wavelength identifiers, to
assign to the optical signal based on the wavelength identifier
graph.
8. A system comprising, one or more devices configured to:
determine topology information for a set of optical signals
associated with an optical network that includes a set of optical
nodes and a set of optical links, the topology information
identifying a set of lightpath conflicts associated with the set of
optical links and/or the set of optical nodes; the topology
information corresponding to a graph that includes a set of
vertices corresponding to the set of optical signals and a set of
edges corresponding to the set of lightpath conflicts; selectively
assign a set of wavelengths to the set of optical signals based on
the graph; and cause a plurality of optical nodes, of the set of
optical nodes, to transmit or receive the set of optical signals
using the assigned set of wavelengths.
9. The system of claim 8, where an optical node, of the plurality
of optical nodes, includes a first optical transmitter and a second
optical transmitter; and where the one or more devices, when
selectively assigning the set of wavelengths, are further
configured to: determine that the set of wavelengths does not
include a particular wavelength that is tunable and routable for a
particular optical signal of the set of optical signals; and cause
the particular optical signal to be moved from the first optical
transmitter to the second optical transmitter.
10. The system of claim 9, where the one or more devices are
further configured to: activate the second optical transmitter.
11. The system of claim 9, where the first optical transmitter is
associated with a first photonic integrated circuit and the second
optical transmitter is associated with a second photonic integrated
circuit.
12. The system of claim 8, where an optical node, of the plurality
of optical nodes, includes a first optical receiver and a second
optical receiver; and where the one or more devices, when
selectively assigning the set of wavelengths, are further
configured to: determine that the set of wavelengths does not
include a particular wavelength that is tunable and routable for a
particular optical signal of the set of optical signals; and cause
the optical signal to be moved from the first optical receiver to
the second optical receiver.
13. The system of claim 12, where the one or more devices are
further configured to: activate the second optical receiver.
14. The system of claim 8, where the one or more devices are
further configured to: determine a set of saturation degrees for
the set of optical signals, a saturation degree, of the set of
saturation degrees, being determined for an optical signal, of the
set of optical signals, based on a quantity of wavelength
identifiers, of a set of wavelength identifiers, associated with
neighboring vertices of a particular vertex corresponding to the
optical signal; and where the one or more devices, when selectively
assigning the set of wavelengths, are further to: selectively
assign the set of wavelengths in an order determined based on the
set of saturation degrees.
15. A method, comprising: determining, by a device, a wavelength
identifier graph corresponding to an optical network based on a set
of lightpath conflicts, for a set of optical signals, associated
with a set of links and a set of nodes of the optical network, one
or more optical signals, of the set of optical signals, being
associated with transmission from a first node, of the set of
nodes, to a second node, of the set of nodes, via a super-channel,
the first node including a transmitter photonic integrated circuit,
the second node including a receiver photonic integrated circuit;
selectively assigning, by the device, a wavelength identifier to an
optical signal, of the set of optical signals, based on the
wavelength identifier graph, the wavelength identifier being
associated with a set of wavelength identifiers and corresponding
to a wavelength of a set of wavelengths; and causing, by the
device, the optical signal to utilize the wavelength, of the set of
wavelengths, for transmission via the optical network.
16. The method of claim 15, where a node, of the set of nodes,
includes an optical transmitter; and where causing the optical
signal to utilize the wavelength further comprises: causing the
optical transmitter associated with the node, of the set of nodes,
to transmit the optical signal at the wavelength.
17. The method of claim 15, where a node, of the set of nodes,
includes an optical receiver; and where causing the optical signal
to utilize the wavelength further comprises: causing the optical
receiver associated with the node, of the set of nodes, to receive
the optical signal at the wavelength.
18. The method of claim 15, where selectively assigning the
wavelength identifier further comprises: determining that the set
of wavelengths does not include a particular wavelength that is
tunable and routable for the optical signal; and causing the
optical signal to be moved from a first transmitter associated with
a first node, of the set of nodes, to a second transmitter
associated with a second node, of the set of nodes.
19. The method of claim 15, further comprising: selecting the
optical signal from the set of optical signals based on at least
one of: a saturation degree for a vertex, the vertex representing
the optical signal in the wavelength identifier graph, the
saturation degree being associated with a quantity of wavelength
identifiers associated with a set of neighboring vertices
representing other optical signals in the wavelength identifier
graph; a degree of the vertex, the degree of the vertex being
associated with a quantity of edges of the wavelength identifier
graph adjacent to the vertex, an edge, of the quantity of edges,
representing a lightpath conflict of the set of lightpath
conflicts; or a quantity of unassigned neighbors, the quantity of
unassigned neighbors being associated with a quantity of vertices
neighboring the vertex that have not been assigned a respective
wavelength identifier.
20. The method of claim 15, where selectively assigning the
wavelength identifier further comprises: selecting a particular
wavelength identifier, of the set of wavelength identifiers, to
assign to the optical signal; determining that the optical signal
is not routable based on selecting the particular wavelength
identifier; and selecting another wavelength identifier, of the set
of wavelength identifiers, to assign to the optical signal based on
the wavelength identifier graph, the other wavelength identifier
corresponding to another wavelength of the set of wavelengths.
Description
RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. .sctn.119
to U.S. Provisional Patent Application No. 62/041,325, filed on
Aug. 25, 2014, the content of which is incorporated by reference
herein in its entirety.
BACKGROUND
[0002] Wavelength division multiplexed (WDM) optical communication
systems (referred to as "WDM systems") are systems in which
multiple optical signals, each having a different wavelength, are
combined onto a single optical fiber using an optical multiplexer
circuit (referred to as a "multiplexer"). Such systems may include
a transmitter circuit, such as a transmitter (Tx) photonic
integrated circuit (PIC) having a transmitter component to provide
a laser associated with each wavelength, a modulator configured to
modulate the output of the laser, and a multiplexer to combine each
of the modulated outputs (e.g., to form a combined output or WDM
signal), which may be collectively integrated onto a common
semiconductor substrate.
[0003] A WDM system may also include a receiver circuit, such as a
receiver (Rx) PIC, having a photodiode, and an optical
demultiplexer circuit (referred to as a "demultiplexer") configured
to receive the combined output and demultiplex the combined output
into individual optical signals.
[0004] A WDM system may also include a set of nodes (e.g., devices
of the WDM system that may be utilized to route the multiple
optical signals, add another optical signal to the multiple optical
signals, drop an optical signal from the multiple optical signals,
or the like. For example, the WDM system may include a set of
reconfigurable optical add-drop multiplexers (ROADMs).
[0005] A wavelength of an optical signal output from the Tx PIC may
be utilized to transmit information at a fixed data rate. However,
multiple optical signals may be combined into a unified channel
that facilitates transmission of information at a higher data rate
(e.g., a super-channel). The multiple optical signals may or may
not be contiguous with respect to the wavelength spectrum. One or
more sets of optical signals may be associated into one or more
super-channels for independent routing through a network.
SUMMARY
[0006] According to some possible implementations, an apparatus may
determine a set of optical signals associated with an optical
network including a set of optical links and a set of optical
nodes. The apparatus may determine topology information for the set
of optical signals and the optical network. The topology
information may include information identifying a particular set of
lightpath conflicts. The particular set of lightpath conflicts may
include a first set of lightpath conflicts associated with the set
of optical links and a second set of lightpath conflicts associated
with the set of optical nodes. The topology information may
correspond to a wavelength identifier graph. The wavelength
identifier graph may include a set of vertices corresponding to the
set of optical signals and a set of edges corresponding to the
first set of lightpath conflicts and the second set of lightpath
conflicts. The apparatus may select an optical signal, from the set
of optical signals, based on the wavelength identifier graph. The
apparatus may selectively assign a wavelength identifier, of a set
of wavelength identifiers, to the optical signal based on the
wavelength identifier graph. The wavelength identifier, of the set
of wavelength identifiers, may correspond to a wavelength of a set
of wavelengths. The apparatus may cause the optical signal to
utilize the wavelength, of the set of wavelengths, for transmission
via one or more super-channels of the optical network.
[0007] According to some possible implementations, one or more
devices may determine topology information for a set of optical
signals associated with an optical network that includes a set of
optical nodes and a set of optical links. The topology information
may identify a set of lightpath conflicts associated with the set
of optical links and/or the set of optical nodes. The topology
information may correspond to a graph that includes a set of
vertices corresponding to the set of optical signals and a set of
edges corresponding to the set of lightpath conflicts. The one or
more devices may selectively assign a set of wavelengths to the set
of optical signals based on the graph. The one or more devices may
cause a plurality of optical nodes, of the set of optical nodes, to
transmit or receive the set of optical signals using the assigned
set of wavelengths.
[0008] According to some possible implementations, a method may
include determining, by a device, a wavelength identifier graph
corresponding to an optical network based on a set of lightpath
conflicts, for a set of optical signals, associated with a set of
links and a set of nodes of the optical network. One or more
optical signals may be associated with transmission via a
super-channel. The method may further include selectively
assigning, by the device, a wavelength identifier to an optical
signal, of the set of optical signals, based on the wavelength
identifier graph. The wavelength identifier being associated with a
set of wavelength identifiers and corresponding to a wavelength of
a set of wavelengths. The method may further include causing, by
the device, the optical signal to utilize the wavelength, of the
set of wavelengths, for transmission via the optical network.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIGS. 1A-1C are diagrams of an overview of an example
implementation described herein;
[0010] FIGS. 2A-2C are diagrams of an example environment in which
systems and/or methods, described herein, may be implemented;
[0011] FIG. 3 is a diagram of example components of a
reconfigurable optical add-drop multiplexer, shown in FIGS. 2A-2C,
that may facilitate adding/dropping an optical signal of a
super-channel and maintaining other optical signals of the
super-channel;
[0012] FIG. 4 is a diagram of example components of a receive
portion shown in FIG. 3;
[0013] FIGS. 5A and 5B are diagrams of example components of a
transmit portion shown in FIG. 3;
[0014] FIGS. 6A and 6B are flow charts of an example process for
performing optical signal wavelength assignment that accords with
constraints on tunability and routability; and
[0015] FIG. 7 is a diagram of example components of one or more
devices described herein.
DETAILED DESCRIPTION
[0016] The following detailed description of example
implementations refers to the accompanying drawings. The same
reference numbers in different drawings may identify the same or
similar elements.
[0017] An optical transmitter associated with a wavelength division
multiplexed (WDM) optical communication system may transmit
multiple optical signals via a single optical communication path
using an optical multiplexer circuit. The optical transmitter may
provide the multiple optical signals along one or more wavelengths
via one or more super-channels. The optical transmitter may
transmit the one or more super-channels that include the multiple
optical signals to a receive node, which may include an optical
receiver, of a network. When an optical signal is added/dropped at
a node of the network, wavelengths, at which a set of optical
signals are to be transmitted/received, may be re-assigned among
the set of optical signals.
[0018] The optical signals that are transmitted via an optical
communication path (e.g., an optical fiber, a link, or the like)
may be assigned different wavelengths to avoid a fiber lightpath
conflict, a photonic integrated circuit (PIC) lightpath conflict,
or the like. A conflict (e.g., multiple optical signals utilizing
the same wavelength via the same optical communication path) may
cause signal degradation, erroneous data reception, or the like. A
fiber lightpath conflict may occur when an optical signal within a
super-channel is added to an optical communication path that
already includes another optical signal with the same wavelength. A
PIC lightpath conflict may occur when an optical signal, which is
being transmitted from/to a particular PIC, conflicts with another
optical signal, which is being transmitted from/to the particular
PIC. An optical signal may include a tunability constraint, a
routability constraint, or another similar constraint. A tunability
constraint may refer to a set of wavelengths to which a
transmitter/receiver PIC associated with transmitting/receiving the
optical signal may tune. A routability constraint may refer to a
restraint on a quantity of directions on which a set of optical
signals transmitted by/received from a PIC may be routed.
[0019] Implementations, described herein, may facilitate
adding/dropping an optical signal of a super-channel by a
reconfigurable optical add-drop multiplexer (ROADM) without adding
and/or dropping one or more other optical signals of the
super-channel. Additionally, or alternatively, implementations,
described herein, may facilitate a wavelength assignment for a set
of optical signals being transmitted via a super-channel that
avoids a fiber lightpath conflict, a PIC lightpath conflict, or the
like, and that accords with a tunability constraint, a routability
constraint, and/or another similar constraint.
[0020] FIGS. 1A-1C are diagrams of an overview of an example
implementation 100 described herein. As shown in FIG. 1A, a set of
optical signals (e.g., OS-1, OS-2, OS-3, OS-4, OS-5, OS-6, and
OS-7) may be transmitted over a network. A network management
device may determine a fiber topology for the network. The fiber
topology of the network may include a set of nodes (e.g., Node A,
Node B, Node C, Node D, and Node E). The set of nodes may include a
set of ROADMs that may permit add/drop of an optical signal, of a
set of optical signals included in a super-channel, without
adding/dropping other optical signals of the set of optical
signals. The set of nodes may be connected by a set of fiber
optical communication paths (e.g., f0, f1, f2, and f3). For
example, a Tx PIC associated with a ROADM of Node A may transmit
OS-1 via f1 to an Rx PIC associated with a ROADM of Node B.
Similarly, a Tx PIC associated with the ROADM of Node B may
transmit OS-5 via f2 and f3 to an Rx PIC associated with a ROADM of
Node D.
[0021] With respect to FIG. 1B, the network management device may
determine a logical topology for the network that identifies a set
of fiber lightpath conflicts, a set of PIC lightpath conflicts, or
the like associated with the network. For example, the network
management device may determine that the Tx PIC associated with the
ROADM of Node A may transmit OS-1 and OS-4 via fiber path 1,
potentially causing fiber lightpath conflict .PSI.-1. Similarly,
the network management device may determine that other fiber paths
may be associated with a potential fiber lightpath conflict (e.g.,
fiber path f0 with potential lightpath conflict .PSI.-0, fiber path
f2 with potential lightpath conflict .PSI.-2, and fiber path f3
with potential lightpath conflict .omega.-3). Additionally, or
alternatively, the network management device may determine that
OS-1, OS-2, and OS-5 may be transmitted/received via a Tx PIC/Rx
PIC associated with the ROADM of Node B, potentially causing PIC
lightpath conflict .PSI.-5. Similarly, the network management
device may determine that other nodes may be associated with a
potential PIC lightpath conflict (e.g., Node A with .PSI.-4, Node C
with .PSI.-6, Node D with .PSI.-7, and Node E with .PSI.-8).
[0022] With respect to FIG. 1C, the network management device may
generate a wavelength identifier graph representing the logical
topology of the optical signals. An optical signal, of the set of
optical signals, may be represented by a vertex of the wavelength
identifier graph. A lightpath conflict (e.g., a potential fiber
lightpath conflict, a potential PIC lightpath conflict, or the
like), of the set of lightpath conflicts, may be represented by an
edge of the wavelength identifier graph. A particular edge,
associated with a particular lightpath conflict, may connect to a
pair of vertices associated with a pair of optical signals. An edge
may be associated with multiple lightpath conflicts. For example, a
first edge associated with .PSI.-0 and a second edge associated
with .PSI.-8 would both connect to a pair of vertices associated
with OS-6 and OS-7 because .PSI.-0 is associated with f6 which
carries OS-6 and OS-7 and .PSI.-8 is associated with Node E which
transmits OS-6 and OS-7. In this case, the first edge and the
second edge may be consolidated into a single edge (e.g.,
represented as ".PSI.-0, .PSI.-8").
[0023] With respect to FIG. 1C, the network management device may
select a particular vertex for wavelength assignment and may select
a wavelength identifier, such that the particular vertex is not
assigned the same wavelength identifier as another vertex with
which the particular vertex shares an edge. In other words, an
optical signal, of a super-channel, associated with a vertex may be
assigned a wavelength for transmission via the super-channel, so
that a lightpath conflict does not result in interference with
another optical signal of the super-channel. The network management
device may determine whether the wavelength associated with the
wavelength identifier is tunable by a Tx PIC of a first ROADM
associated with transmitting the particular optical signal and an
Rx PIC of a second ROADM associated with receiving the particular
optical signal. The network management device may determine whether
the wavelength is routable based on a limited degrees of
routability for the Tx PIC and the Rx PIC. If the wavelength of the
particular optical signal conflicts with the wavelength of another
optical signal, is not tunable, and/or is not routable, the network
management device may select another available wavelength
identifier associated with another wavelength. If no other
wavelength identifier is available, the network management device
may assign the optical signal to another PIC (e.g., another Tx PIC
of the first ROADM, another Rx PIC of the second ROADM, or the
like) and may update the wavelength identifier graph (e.g., to
remove the optical signal from the wavelength identifier graph, to
remove lightpath conflicts associated therewith, or the like). If
the wavelength does not conflict with the wavelength of another
optical signal, is tunable, and is routable, the network management
device may assign the wavelength to the particular optical signal
and may perform wavelength assignment for one or more other optical
signals (e.g., iteratively) until wavelength assignment is
complete.
[0024] In this way, a network management device may efficiently
perform wavelength assignment that accords with constraints on
tunability and routability for a set of optical signals that may be
added and/or dropped by a ROADM at a node of a network.
[0025] FIGS. 2A-2C are diagrams of an example environment 200 in
which systems and/or methods, described herein, may be implemented.
As shown in FIG. 2A, environment 200 may include a network
management device 210, and an optical network 220, which may
include a set of network devices 230-1 through 230-N(N.gtoreq.1)
(hereinafter referred to individually as "network device 230," and
collectively as "network devices 230"). Devices of environment 200
may interconnect via wired connections, wireless connections, or a
combination of wired and wireless connections.
[0026] Network management device 210 may include one or more
devices capable of receiving, generating, storing, processing,
and/or providing information associated with a network (e.g.,
optical network 220). For example, network management device 210
may include a computing device, such as a server or a similar type
of device. Network management device 210 may assist a user in
modeling and/or planning a network, such as optical network 220.
For example, network management device 210 may assist in modeling
and/or planning an optical network configuration, which may include
quantities, locations, capacities, parameters, and/or
configurations of network devices 230. In some implementations,
network management device 210 may determine a wavelength assignment
for a set of optical signals being provided via a set of network
devices 230. In some implementations, network management device 210
may be associated with a user interface. In some implementations,
network management device 210 may be a distributed device
associated with one or more network devices 230. In some
implementations, network management device 210 may be separate from
network device 230, but may be linked to network device 230 via a
protocol interface, such as an application programming interface,
or the like.
[0027] Optical network 220 may include any type of network that
uses light as a transmission medium. For example, optical network
220 may include a fiber-optic based network, an optical transport
network, a light-emitting diode network, a laser diode network, an
infrared network, and/or a combination of these or other types of
optical networks. Optical network 220 may include one or more
optical routes (e.g., optical lightpaths) that may specify a route
along which light is carried (e.g., using one or more optical
links) between two or more network devices 230 (e.g., via an
optical link). An optical link may include an optical fiber, an
optical control channel, an optical data channel, or the like, and
may carry an optical channel (e.g., a signal associated with a
particular wavelength of light), an optical super-channel (e.g., a
set of optical signals), a super-channel set, an optical carrier
set, a set of spectral slices, or the like.
[0028] Network device 230 may include one or more devices capable
of receiving, generating, storing, processing, and/or providing
data carried by an optical signal via an optical link. For example,
network device 230 may include one or more optical data processing
and/or optical traffic transfer devices, such as an optical
amplifier (e.g., a doped fiber amplifier, an erbium doped fiber
amplifier, a Raman amplifier, etc.), an optical add-drop
multiplexer (OADM) (e.g., a reconfigurable optical add-drop
multiplexer (ROADM), a flexibly reconfigurable optical add-drop
multiplexer ("FROADM") that may utilize a flexible wavelength grid,
etc.), an optical source device (e.g., a laser source), an optical
destination device (e.g., a laser sink), an optical multiplexer, an
optical demultiplexer, an optical transmitter, an optical receiver,
an optical transceiver, a photonic integrated circuit (PIC), an
integrated optical circuit, or the like. In some implementations,
network device 230 may include one or more optical components.
Network device 230 may process and/or transmit an optical signal
(e.g., to another network device 230 via an optical link) to
deliver the optical signal through optical network 220.
[0029] The number and arrangement of devices and networks shown in
FIG. 2A are provided as an example. In practice, there may be
additional devices and/or networks, fewer devices and/or networks,
different devices and/or networks, or differently arranged devices
and/or networks than those shown in FIG. 2A. Furthermore, two or
more devices shown in FIG. 2A may be implemented within a single
device, or a single device shown in FIG. 2A may be implemented as
multiple, distributed devices. Additionally, or alternatively, a
set of devices (e.g., one or more devices) of environment 200 may
perform one or more functions described as being performed by
another set of devices of environment 200.
[0030] FIG. 2B is a diagram of example devices of optical network
220 that may be designed, monitored, and/or configured according to
implementations described herein. One or more devices shown in FIG.
2B may operate within optical network 220, and may correspond to
one or more network devices 230 and/or one or more optical
components of a network device 230. As shown, optical network 220
may include a set of optical transmitter devices 240-1 through
240-M (M.gtoreq.1) (hereinafter referred to individually as "Tx
device 240," and collectively as "Tx devices 240"), a set of
super-channels 245-1 through 245-M (M.gtoreq.1) (hereinafter
referred to individually as "super-channel 245," and collectively
as "super-channels 245"), a multiplexer ("MUX") 250, a set of
ROADMs 260-1 through 260-L (L.gtoreq.1) (hereinafter referred to
individually as "ROADM 260," and collectively as "ROADMs 260"), a
demultiplexer ("DEMUX") 270, and one or more optical receiver
devices 275-1 through 275-K (K.gtoreq.1) (hereinafter referred to
individually as "Rx device 275," and collectively as "Rx devices
275").
[0031] Tx device 240 may include, for example, an optical
transmitter and/or an optical transceiver that generates an optical
signal. For example, Tx device 240 may include one or more
integrated circuits, such as a transmitter photonic integrated
circuit (PIC), an application specific integrated circuit (ASIC),
or the like. In some implementations, Tx device 240 may include a
laser associated with each wavelength, a digital signal processor
to process digital signals, a digital-to-analog converter to
convert the digital signals to analog signals, a modulator to
modulate the output of the laser, and/or a multiplexer to combine
each of the modulated outputs (e.g., to form a combined output or
WDM signal). One or more optical signals may be carried as
super-channel 245. In some implementations, a single Tx device 240
may be associated with a single super-channel 245. In some
implementations, a single Tx device 240 may be associated with
multiple super-channels 245, or multiple Tx devices 240 may be
associated with a single super-channel 245. In some
implementations, Tx device 240 may correspond to and/or include one
or more components described herein with regards to FIG. 5A.
[0032] Super-channel 245 may include multiple channels (e.g.,
optical signals) multiplexed together using wavelength-division
multiplexing to increase transmission capacity. Various quantities
of channels may be combined into super-channels using various
modulation formats to create different super-channel types having
different characteristics. Additionally, or alternatively, an
optical link may include a super-channel set. A super-channel set
may include multiple super-channels multiplexed together using
wavelength-division multiplexing to increase transmission
capacity.
[0033] Multiplexer 250 may include, for example, an optical
multiplexer (e.g., an arrayed waveguide grating (AWG)) that
combines multiple input super-channels 245 for transmission via an
output fiber). For example, multiplexer 250 may combine
super-channels 245-1 through 245-M, and may provide the combined
super-channels 245 to ROADM 260 via an optical link (e.g., a
fiber).
[0034] ROADM 260 may include, for example, an OADM, a ROADM, a
FROADM, or the like. ROADM 260 may multiplex, de-multiplex, add,
drop, and/or route multiple super-channels 245 into and/or out of a
fiber (e.g., a single mode fiber). As illustrated, a particular
ROADM 260, of the set of ROADMs 260, may drop super-channel 245-1
from a fiber, and may allow super-channels 245-2 through 245-M to
continue propagating toward Rx device 275 and/or another ROADM 260.
Dropped super-channel 245-1 may be provided to a device (not shown)
that may demodulate and/or otherwise process super-channel 245-1 to
output the data stream carried by super-channel 245-1. As further
shown, ROADM 260 may add super-channel 245-1' to the fiber.
Super-channel 245-1' and super-channels 245-2 through 245-M may
propagate to demultiplexer 270 and/or another ROADM 260. A network
including multiple ROADMs 260 is described in more detail herein in
connection with FIG. 2C. Example components of ROADM 260 are
described in more detail herein in connection with FIG. 3, FIG. 4,
and FIGS. 5A and 5B.
[0035] Demultiplexer 270 may include, for example, an optical
de-multiplexer (e.g., an arrayed waveguide grating) that separates
multiple super-channels 245 carried over an input fiber. For
example, demultiplexer 270 may separate super-channels 245-1' and
super-channels 245-2 through 245-M, and may provide each
super-channel 245 to a corresponding Rx device 275.
[0036] Rx device 275 may include, for example, an optical receiver
and/or an optical transceiver that receives an optical signal. For
example, Rx device 275 may include one or more integrated circuits,
such as a receiver PIC, an ASIC, or the like. In some
implementations, Rx device 275 may include a demultiplexer to
receive combined output and demultiplex the combined output into
individual optical signals, a photodetector to convert an optical
signal to a voltage signal, an analog-to-digital converter to
convert voltage signals to digital signals, and/or a digital signal
processor to process the digital signals. One or more optical
signals may be received by Rx device 275 via super-channel 245. Rx
device 275 may convert a super-channel 245 into one or more
electrical signals, which may be processed to output information
associated with each data stream carried by an optical channel
included in super-channel 245. In some implementations, a single Rx
device 275 may be associated with a single super-channel 245. In
some implementations, a single Rx device 275 may be associated with
multiple super-channels 245, or multiple Rx devices 275 may be
associated with a single super-channel 245. In some
implementations, Rx device 275 may correspond to and/or include one
or more components described herein with regards to FIG. 4. In some
implementations, Rx device 275 and Tx device 240 may be implemented
on a common substrate, such as a Tx/Rx PIC.
[0037] One or more devices shown in FIG. 2B may correspond to a
single network device 230. In some implementations, a combination
of devices shown in FIG. 2B correspond to a single network device
230. For example, Tx devices 240-1 through 240-M and multiplexer
250 may correspond to a single network device 230. As another
example, Rx devices 275-1 through 275-K and demultiplexer 270 may
correspond to a single network device 230.
[0038] The number and arrangement of devices shown in FIG. 2B are
provided as an example. In practice, there may be additional
devices, fewer devices, different devices, or differently arranged
devices, included in optical network 220, than those shown in FIG.
2B. Furthermore, two or more devices shown in FIG. 2B may be
implemented within a single device, or a single device shown in
FIG. 2B may be implemented as multiple, distributed devices.
Additionally, or alternatively, a set of devices shown in FIG. 2B
may perform one or more functions described as being performed by
another set of devices shown in FIG. 2B.
[0039] FIG. 2C is a diagram of an example configuration of a
network of multiple ROADMs 260 that may be designed, monitored,
and/or configured as described herein. One or more ROADMs 260 shown
in FIG. 2C may operate within optical network 220 of FIG. 2B.
[0040] As shown in FIG. 2C, optical network 220 may include a set
of ROADMs 260-1 through 260-5 (e.g., nodes of a network) that may
facilitate communication via optical network 220. Network device
230 (e.g., Tx device 240, Rx device 275, or the like) may
output/receive super-channel 245 to/from ROADM 260-1 via optical
link 280 (e.g., an optical fiber). ROADM 260-1 may be connected via
a first optical link 280 to ROADM 260-2 and via a second optical
link 280 to ROADM 260-5. Furthermore, for example, ROADM 260-2 may
be connected via a first optical link 280 to ROADM 260-3 and via a
second optical link 280 to ROADM 260-4. Super-channel 245 may
include a set of optical signals 285-1 through 285-3. In some
implementations, ROADM 260 may perform first node routing by, as a
first node that receives a super-channel from a source of the
super-channel, routing individual optical signals 285 of a
super-channel to different ROADMs 260. In other words, a particular
ROADM 260 that receives the individual optical signals 285 from a
source of the individual optical signals 285 (e.g., network device
230), performs routing for the individual optical signals 285 to a
set of other ROADMs 260. For example, ROADM 260-1 may receive
optical signal 285-1 from network device 230 (e.g., Tx device 240)
and may route optical signal 285-1 to ROADM 260-5 and may receive
optical signal 285-2 from network device 230 (e.g., Tx device 240)
and may route optical signal 285-2 to ROADM 260-2.
[0041] The number and arrangement of devices and/or signals shown
in FIG. 2C are provided as an example. In practice, there may be
additional devices and/or signals, fewer devices and/or signals,
different devices and/or signals, or differently arranged devices
and/or signals, included in optical network 220, than those shown
in FIG. 2C. Furthermore, two or more devices shown in FIG. 2C may
be implemented within a single device, or a single device shown in
FIG. 2C may be implemented as multiple, distributed devices.
Additionally, or alternatively, a set of devices shown in FIG. 2C
may perform one or more functions described as being performed by
another set of devices shown in FIG. 2C.
[0042] FIG. 3 is a diagram of components of ROADM 260 shown in
optical network 220 of FIG. 2B. As shown in FIG. 3, ROADM 260 may
include a set of wavelength selective switches (WSSs) 310-1 through
310-6 (hereinafter referred to individually as "WSS 310," and
collectively as "WSSs 310"), a set of optical links 280-1 through
280-6, a receive portion 330 which may include one or more
receivers 335-1 through 335-G (G.gtoreq.1) (hereinafter referred to
individually as "receiver 335," and collectively as "receivers
335"), and a transmit portion 340, which may include one or more
transmitters 345-1 through 345-H (H.gtoreq.1) (hereinafter referred
to individually as "transmitter 345," and collectively as
"transmitters 345").
[0043] WSS 310 may include, for example, a switching array that may
direct an optical signal. For example, a WSS 310 (e.g., WSS 310-1,
WSS 310-4, and WSS 310-6 may receive a set of super-channels 245
via a corresponding optical link 280 (e.g., optical link 280-1,
optical link 280-4, and optical link 280-6) and may selectively
direct the set of super-channels to another WSS 310 (e.g., WSS
310-2, WSS 310-3, and WSS 310-5) for output to another ROADM 260
via another optical link 280 (e.g., optical link 280-2, optical
link 280-3, and optical link 280-5). In some implementations, WSS
310 may receive super-channel 245 from transmit portion 340 for
output to another ROADM 260. Additionally, or alternatively, WSS
310 may provide super-channel 245 to receive portion 330. In some
implementations, WSS 310 may receive multiple super-channels 245
via optical link 280 and may provide a portion of the
super-channels 245 to a first WSS 310 for output to a first ROADM
260 and another portion of the super-channels 245 to a second WSS
310 for output to a second ROADM 260. For example, WSS 310-1 may
receive, via optical link 280-1, super-channel 245-1, super-channel
245-2, and super-channel 245-3, and WSS 310-1 may provide
super-channel 245-1 to WSS 310-3 for output to ROADM 260-1, may
provide super-channel 245-2 to WSS 310-5 for output to ROADM 260-1,
and may provide super-channel 245-3 to receive portion 330.
[0044] Receive portion 330 may include one or more devices
associated with receiving, processing, providing and/or routing
super-channel 245 and/or optical signal 285. In some
implementations, receive portion 330 may include one or more
receivers 335-1 through 335-G as discussed herein with regard to
FIG. 4. In some implementations, receive portion 330 may include a
splitting device (not shown) associated with routing received
optical signals to receivers 335. For example, receive portion 330
may include a power splitter, a demultiplexer, an arrayed waveguide
grating, or the like, which may route an optical signal of a
super-channel to receiver 335. In some implementations, receive
portion 330 may receive a super-channel including polarization
multiplexed optical signals and may separate a transverse electric
(TE) polarization portion and a transverse mechanic (TM)
polarization portion of a particular optical signal of the
super-channel. In this case, a splitting device of receive portion
330 may provide the TE polarization portion to a first receiver 335
and may provide the TM polarization portion of the particular
optical signal to a second receiver 335.
[0045] Transmit portion 340 may include one or more devices
associated with receiving, processing, providing, and/or routing
super-channel 245 and/or optical signal 285. In some
implementations, transmit portion 340 may include one or more
transmitters 345-1 through 345-H as discussed herein with regard to
FIGS. 5A and 5B. In some implementations, transmitters 345 may
provide a set of super-channels that may be routed to one or more
WSSs 310 for transmission to another ROADM 260 or a network device
230. In some implementations, transmit portion 340 may utilize a
single PIC that includes multiple transmitters 345. For example,
transmit portion 340 may include a particular PIC that may transmit
multiple optical signals via multiple wavelengths that may be
independently adjusted by tuning a laser associated with the PIC, a
local oscillator associated with the PIC, or the like.
[0046] While FIG. 3 shows ROADM 260 as including a particular
quantity and arrangement of components, in some implementations,
ROADM 260 may include additional components, fewer components,
different components, or differently arranged components.
[0047] FIG. 4 is a diagram of example components of receiver 335
associated with receive portion 330 as shown in FIG. 3. As shown in
FIG. 4, receiver 335 may include a local oscillator 410, one or
more hybrid mixers 420, one or more detectors 430, one or more
analog-to-digital converters (ADCs) 440, and/or an Rx DSP 450. In
some implementations, local oscillator 410, hybrid mixer 420,
detectors 430, ADCs 440, and/or Rx DSP 450 may be implemented on
one or more integrated circuits, such as one or more PICs, one or
more ASICs, etc.
[0048] Local oscillator 410 may include a laser device. In some
implementations, local oscillator 410 may provide a reference
signal to hybrid mixer 420. In some implementations, local
oscillator 410 may include a single-sided laser to provide an
optical signal to hybrid mixer 420. In some other implementations,
local oscillator 410 may include a double-sided laser to provide
multiple optical signals to multiple hybrid mixers 420. In some
implementations, a phase, intensity, and/or amplitude of the
reference signal may be compared to a phase, intensity, and/or
amplitude of an input signal (e.g., another optical signal) to
recover data carried by the input signal. In some implementations,
the input signal may be received from a power splitter (not shown),
that may provide a power-split portion of a super-channel as the
input signal. In some implementations, the input signal may
processed via a component of a demultiplexer (e.g., an arrayed
waveguide grating (AWG), or the like) that may output a set of
optical signals of a super-channel on a set of waveguides
processing.
[0049] Hybrid mixer 420 may include one or more optical devices to
receive an input signal (e.g., an optical signal of a
super-channel). In some implementations, hybrid mixer 420 may
receive a reference signal from local oscillator 410. In some
implementations, hybrid mixer 420 may supply components associated
with the input signal and the reference signal to detectors 430.
For example, hybrid mixer 420 may supply an in-phase x-polarization
(e.g., x-pol) component, a quadrature x-pol component, an in-phase
y-polarization (e.g., y-pol) component, and a quadrature y-pol
component. In some implementations, a first hybrid mixer 420 may
provide the in-phase x-pol component and the quadrature x-pol
component, and a second hybrid mixer 420 may provide the in-phase
y-pol component and the quadrature y-pol component.
[0050] Detector 430 may include one or more photodetectors, such as
a photodiode, to receive the output optical signal, from hybrid
mixer 420, and convert the output optical signal to corresponding
voltage signals. In some implementation, receiver 335 may include
multiple detectors 430 for in-phase x-pol components, quadrature
x-pol components, in-phase y-pol components, and quadrature y-pol
components. In some implementations, detectors 430 may include one
or more balanced pairs of photodetectors. For example, detectors
430 may include a first pair of photodetectors to receive an
in-phase x-pol component, and a second pair of photodetectors to
receive a quadrature x-pol component. Additionally, detectors 430
may include a third pair of photodetectors to receive an in-phase
y-pol component, and a fourth pair of photodetectors to receive a
quadrature y-pol component.
[0051] ADC 440 may include an analog-to-digital converter that
converts the voltage signals from detector 430 to digital signals.
ADC 440 may provide the digital signals to Rx DSP 450. In some
implementations, optical receiver 253 may include four ADCs 440 or
some other number of ADCs 440 (e.g., one ADC 440 for each
electrical signal output by detectors 430).
[0052] Rx DSP 450 may include a digital signal processor or a
collection of digital signal processors. In some implementations,
Rx DSP 450 may receive digital signals from ADCs 440 and may
process the digital signals to form output data associated with the
input signal received by hybrid mixer 420. In some implementations,
a set of processing circuits (e.g., that include clock and data
recovery circuitry) may demodulate and output data associated with
the digital signals.
[0053] While FIG. 4 shows receiver 335 as including a particular
quantity and arrangement of components, in some implementations,
receiver 335 may include additional components, fewer components,
different components, or differently arranged components.
[0054] FIGS. 5A and 5B are diagrams of example components of
transmit portion 340 shown in ROADM 220 of FIG. 3.
[0055] As shown in FIG. 5A, transmitter 345 of transmit portion 340
may include a Tx DSP 510, one or more DACs 520, a laser 530, and
one or more modulators 540. In some implementations, Tx DSP 510,
DACs 520, laser 530, and/or modulators 540 may be implemented on
one or more integrated circuits, such as one or more PICs, one or
more application specific integrated circuits (ASICs), or the like.
In some implementations, components of multiple optical
transmitters 212 may be implemented on a single integrated circuit,
such as a single PIC, to form a super-channel transmitter.
[0056] Tx DSP 510 may include a digital signal processor or a
collection of digital signal processors. In some implementations,
Tx DSP 510 may receive a data source (e.g., a signal received via a
Tx channel), may process the signal, and may output digital signals
having symbols that represent components of the signal (e.g., an
in-phase x-polarization component, a quadrature x-polarization
component, an in-phase y-polarization component, and a quadrature
y-polarization component).
[0057] DAC 520 may include a digital-to-analog converter or a
collection of digital-to-analog converters. In some
implementations, DAC 520 may receive respective digital signals
from Tx DSP 510, may convert the received digital signals to analog
signals, and may provide the analog signals to modulator 540. The
analog signals may correspond to electrical signals (e.g., voltage
signals) to drive modulator 540. In some implementations,
transmitter 345 may include multiple DACs 520, where a particular
DAC 520 may correspond to a particular polarization (e.g., an
x-polarization, a y-polarization) of a signal and/or a particular
component of a signal (e.g., an in-phase component, a quadrature
component).
[0058] Laser 530 may include a semiconductor laser, such as a
distributed feedback (DFB) laser, or some other type of laser.
Laser 530 may provide an output optical light beam to modulator
540.
[0059] Modulator 540 may include a Mach-Zehnder modulator (MZM),
such as a nested MZM, or another type of modulator. Modulator 540
may receive the optical light beam from laser 530 and the voltage
signals from DAC 520, and may modulate the optical light beam,
based on the voltage signals, to generate a multiple sub-carrier
output signal, which may be provided to a multiplexer.
[0060] In some implementations, transmitter 345 may include
multiple modulators 540, which may be used to modulate signals of
different polarizations. For example, an optical splitter may
receive an optical light beam from laser 530, and may split the
optical light beam into two branches: one for a first polarization
(e.g., an x-polarization) and one for a second polarization (e.g.,
the y-polarization). The splitter may output one optical light beam
to a first modulator 540, which may be used to modulate signals of
the first polarization, and another optical light beam to a second
modulator 540, which may be used to modulate signals of the second
polarization. In some implementations, two DACs 520 may be
associated with each polarization. In these implementations, two
DACs 520 may supply voltage signals to the first modulator 540
(e.g., for an in-phase component of the x-polarization and a
quadrature component of the x-polarization), and two DACs 520 may
supply voltage signals to the second modulator 540 (e.g., for an
in-phase component of the y-polarization and a quadrature component
of the y-polarization). The outputs of modulators 540 may be
combined back together using combiners and polarization
multiplexing. For example, a power-combiner, AWG, or the like (not
shown) may combine a set of modulated optical signals and provide
the output signal.
[0061] In some implementations, transmitter 345 may transmit a set
of optical signals via a set of different wavelengths. For example,
transmitter 345 may transmit a first optical signal via a first
wavelength and a second optical signal via a second wavelength.
Additionally, or alternatively, transmitter 345 may independently
adjust a wavelength, such as by changing a temperature of laser
330, adjusting a quantity of current supplied to laser 330, or the
like. For example, transmitter 345 may alter a first wavelength
associated with a first optical signal without altering a second
wavelength associated with a second optical signal.
[0062] The number and arrangement of components shown in FIG. 5A
are provided as an example. In practice, transmitter 345 may
include additional components, fewer components, different
components, or differently arranged components than those shown in
FIG. 5A. For example, the quantity of DACs 520, lasers 530, and/or
modulators 540 may be selected to implement a transmitter 345 that
is capable of generating polarization diverse signals for
transmission on an optical fiber. Additionally, or alternatively, a
set of components shown in FIG. 5A may perform one or more
functions described herein as being performed by another set of
components shown in FIG. 5A.
[0063] As shown in FIG. 5B, transmit portion 340 may include a set
of transmitters 345-1 through 345-3 and a routing module 550, which
may include a set of splitters 560-1 through 560-3 and a set of
connectors 570-1 through 570-3. In another example, transmit
portion 340 may include another quantity of transmitters 345,
another quantity of splitters 560, another quantity of connectors
570, or the like. In some implementations, each transmitter 345 of
transmit portion 340 may provide a corresponding super-channel
and/or a corresponding set of optical signals to a particular
splitter 560 of routing module 550.
[0064] In some implementations, splitter 560 may receive a
super-channel from transmitter 345 and may provide a power split
portion of the super-channel to a set of connectors 570. For
example, splitter 560-1 may receive a particular super-channel from
transmitter 345-1 and may provide a first portion of the particular
super-channel to connector 570-1, a second portion of the
particular super-channel to connector 570-2, and/or a third portion
of the particular super-channel to connector 570-3. Similarly,
splitter 560-2 and splitter 560-3 may receive other super-channels
from transmitter 345-2 and transmitter 345-3, respectively, and may
provide first portions of the other super-channels to connector
570-1, second portions of the other super-channels to connector
570-2, and/or third portions of the other super-channels to
connector 570-3. In some implementations, connector 570 may provide
a received portion of a super-channel to a particular WSS 310. For
example, connector 570-1 may receive a first portion of a first
super-channel from splitter 560-1, a second portion of a second
super-channel from splitter 560-2, and a third portion of a third
super-channel from splitter 560-3, and connector 570-1 may provide
the first portion, the second portion, and the third portion to WSS
310-1.
[0065] The number and arrangement of devices shown in FIG. 5B are
provided as an example. In practice, there may be additional
devices, fewer devices, different devices, or differently arranged
devices. For example, while transmit portion 340 is shown as
including three transmitters with three splitters and three
connectors, transmit portion 340 may include another quantity of
transmitters with corresponding quantities of splitters and
connectors. Additionally, or alternatively, transmit portion 340
may include another device or set of devices associated with
routing optical signals, such as a switch, or the like.
[0066] FIGS. 6A and 6B are flow charts of an example process 600
for performing optical signal wavelength assignment that accords
with constraints on tunability and routability. In some
implementations, one or more process blocks of FIGS. 6A and 6B may
be performed by network management device 210. In some
implementations, one or more process blocks of FIGS. 6A and 6B may
be performed by another component or a set of components separate
from or including network management device 210, such as a
component associated with network device 230 (e.g., ROADM 260), or
the like.
[0067] As shown in FIG. 6A, process 600 may include assigning a set
of optical signals to a set of photonic integrated circuits (PICs)
(block 605). For example, network management device 210 may assign
the set of optical signals to the set of PICs. In some
implementations, network management device 210 may assign the set
of optical signals to the set PICs at a node of a network (e.g., at
a particular ROADM 260 of optical network 220). In some
implementations, network management device 210 may assign multiple
optical signals to a single PIC. For example, when a node includes
multiple PICs, network management device 210 may assign a first set
of optical signals to a first PIC, of the multiple PICs, and a
second set of optical signals to a second PIC, of the multiple
PICs. Additionally, or alternatively, network management device 210
may assign a first set of optical signals to a first PIC associated
with a first node and a second set of optical signals to a second
PIC associated with a second node.
[0068] As further shown in FIG. 6A, process 600 may include
generating a wavelength identifier graph for the set of optical
signals (block 610). For example, network management device 210 may
generate the wavelength identifier graph for the set of optical
signals. A wavelength identifier graph may refer to a
representation of a logical topology of optical signals being
transmitted by a set of nodes (e.g., a set of ROADMs 260) of a
network. The logical topology may include a set of optical signals
(e.g., that are transmitted between two or more nodes) that may be
represented as vertices of the wavelength identifier graph. The
logical topology may include a set of lightpath conflicts, such as
fiber lightpath conflicts, PIC lightpath conflicts, or the like,
that may be represented as edges of the wavelength identifier
graph. Although a wavelength identifier graph is described, herein,
in terms of a graphical representation, the wavelength identifier
graph may be another representation of a logical topology of
optical signals, such as a text-based representation, a
matrix-based representation, a non-structured representation, or
the like. In some implementations, network management device 210
may determine the logical topology of a set of nodes based on a set
of potential lightpath conflicts associated with optical signals
being transmitted by one or more nodes of the set of nodes. For
example, network management device 210 may determine that a
particular set of optical signals are utilizing a particular set of
links between a particular set of nodes and may identify a
particular set of potential lightpath conflicts associated
therewith. In this case, network management device 210 may generate
a particular wavelength identifier graph that represents the
particular set of optical signals and the particular set of
potential lightpath conflicts. Additionally, or alternatively,
network management device 210 may receive information identifying
the wavelength identifier graph, such as a stored wavelength
identifier graph, or the like.
[0069] As further shown in FIG. 6A, process 600 may include
performing wavelength assignment based on the wavelength identifier
graph (block 615). For example, network management device 210 may
perform wavelength assignment based on the wavelength identifier
graph. Wavelength assignment may refer to assigning a wavelength
identifier (e.g., that corresponds to a wavelength) to an optical
signal. In some implementations, network management device 210 may
utilize a particular algorithm (e.g., Brelaz's algorithm) to
perform wavelength assignment based on the wavelength identifier
graph, as discussed in detail with regards to FIG. 6B. In some
implementations, network management device 210 may perform an
initial wavelength assignment and may determine whether the initial
wavelength assignment satisfies a set of criteria (e.g., a
routability criteria, a tunability criteria, or the like). For
example, network management device 210 may utilize Brelaz's
algorithm to initially assign a set of wavelength identifiers to a
set of optical signals. Additionally, or alternatively, network
management device 210 may perform wavelength assignment without an
initial assignment. For example, network management device 210 may
select an optical signal, from a set of optical signals, according
to a set of selection criteria, may assign a wavelength identifier
to the optical signal (e.g., according to Brelaz's algorithm,
according to a set of assignment criteria, such as saturation
degree, quantity of unassigned neighbors, or the like) and may
confirm that the wavelength identifier assignment does not violate
any constraints. In this case, network management device 210 may
select one or more other optical signals, from the set of optical
signals, for wavelength assignment until network management device
210 has performed wavelength assignment for each optical signal of
the set of optical signals.
[0070] As shown in FIG. 6B, process 600 may include selecting an
optical signal for wavelength assignment (block 620). For example,
network management device 210 may select the optical signal, from
the set of optical signals, for wavelength assignment. In some
implementations, network management device 210 may select the
optical signal based on a saturation degree of the optical signal.
Saturation degree may refer to a quantity of unique wavelength
identifiers assigned to neighboring vertices of the vertex
associated with the optical signal. For example, network management
device 210 may determine that a vertex of the wavelength identifier
graph is neighbored by a first neighboring vertex associated with a
first wavelength identifier, a second neighboring vertex associated
with the first wavelength identifier, and a third neighboring
vertex associated with a second wavelength identifier. In this
case, network management device 210 may determine that, for the
purposes of determining a saturation degree, the vertex of the
wavelength identifier graph is associated with neighboring vertices
having two unique wavelength identifiers. In some implementations,
network management device 210 may select a particular optical
signal associated with a vertex (e.g., of a set of vertices that
are not assigned) that is associated with the highest saturation
degree compared with the set of vertices that are not assigned
(e.g., that have not been assigned a wavelength identifier
corresponding to a wavelength).
[0071] Additionally, or alternatively, network management device
210 may select the optical signal based on a degree of the vertex
associated with the optical signal. A degree of the vertex may
refer to a quantity of edges of the wavelength identifier graph
that touch the vertex. For example, when a vertex is associated
with a set of three edges, network management device 210 may
determine that the degree of the vertex is three. In some
implementations, network management device 210 may select a
particular optical signal associated with a vertex that is
associated with the highest degree of the vertex compared with a
set of other vertices of the wavelength identifier graph that are
not assigned.
[0072] Additionally, or alternatively, network management device
210 may select the optical signal based on a quantity of unassigned
neighbors of the vertex associated with the optical signal. A
quantity of unassigned neighbors refers to the quantity of
neighboring vertices to a vertex that have not been assigned a
wavelength identifier during wavelength assignment. For example,
when a vertex is connected by a first edge to a first vertex
associated with a first wavelength identifier, a second edge to a
second vertex that has not been assigned a wavelength identifier,
and a third edge to a third vertex associated with a second
wavelength identifier, network management device 210 may determine
that the vertex is associated with one unassigned neighbor. In some
implementations, network management device 210 may select a
particular optical signal associated with a vertex that is
associated with the greatest quantity of unassigned neighbors
compared with a set of vertices that are not assigned.
Additionally, or alternatively, network management device 210 may
select the particular optical signal based on the particular
optical signal being associated with the greatest quantity of
unassigned neighbors that share a PIC lightpath conflict with the
optical signal.
[0073] As further shown in FIG. 6B, process 600 may include
selecting a wavelength identifier to assign to the optical signal
(block 625). For example, network management device 210 may select
a wavelength identifier from a set of wavelength identifiers. The
wavelength identifier may correspond to a wavelength of a set of
wavelengths. In some implementations, network management device 210
may select the wavelength identifier based on an ordering of the
set of wavelength identifiers. For example, network management
device 210 may order the set of wavelength identifiers based on
corresponding wavelength, bandwidth (e.g., of a channel associated
with a particular corresponding wavelength), through-put (e.g., of
a channel associated with a particular corresponding wavelength),
or the like and may select the wavelength identifier based on a
selection criteria, such as selecting a wavelength identifier
associated with the lowest corresponding wavelength, the greatest
corresponding wavelength, or the like. In some implementations,
network management device 210 may select the wavelength identifier
based on an assignment algorithm, such as Brelaz's algorithm, or
the like.
[0074] As further shown in FIG. 6B, process 600 may include
determining whether the selected wavelength identifier conflicts
with another optical signal (block 630). For example, network
management device 210 may determine whether the selected wavelength
identifier conflicts with another wavelength identifier assigned to
another vertex associated with another optical signal. In some
implementations, the selected wavelength identifier may conflict
with another wavelength identifier if the vertex, to which the
selected wavelength identifier is assigned, shares an edge with
another vertex that is assigned the same wavelength identifier. For
example, if network management device 210 assigns a first
wavelength identifier to a first vertex that shares an edge with a
second vertex that is assigned the first wavelength identifier,
network management device 210 may determine that the selected
wavelength identifier conflicts with another optical signal.
[0075] As further shown in FIG. 6B, if the selected wavelength
identifier does not conflict with another optical signal (block
630--NO), process 600 may include determining whether the
wavelength is tunable and routable at either end (block 635). For
example, network management device 210 may determine whether the
selected wavelength is both tunable and routable at both ends. An
end may refer to a PIC associated with a first ROADM 260 that
transmits the optical signal and another PIC associated with a
second ROADM 260 that receives the optical signal. In some
implementations, an end may be a PIC that transmits to another PIC
(e.g., another PIC of the same ROADM, another PIC of a different
ROADM, or the like).
[0076] A selected wavelength may be tunable if a PIC associated
with transmitting/receiving the optical signal assigned to the
selected wavelength is configurable to tune to the selected
wavelength. For example, a first PIC (e.g., a Tx PIC) may be
tunable to a first set of wavelengths and a second PIC (e.g., an Rx
PIC) may be tunable to a second set of wavelengths, and network
management device 210 may determine whether the selected wavelength
is included in both the first set of wavelengths and the second set
of wavelengths.
[0077] Routability of a selected wavelength may refer to a set of
constraints limiting a quantity of directions in which optical
signals associated with a particular PIC can be routed. For
example, a first PIC may connect to a particular set of outputs
associated with routing optical signals to a particular set of
ROADMs 260 and a second PIC may connect to another set of outputs
associated with routing optical signals to another set of ROADMs
260. A constraint may be referred to as a limited degree of
routability. In some implementations, network management device 210
may utilize stored information regarding the set of PICs to
determine whether the selected wavelength associated with the
optical signal and the assigned ends (e.g., a Tx PIC associated
with a first ROADM 260 and an Rx PIC associated with a second ROADM
260) is routable.
[0078] As further shown in FIG. 6B, if the selected wavelength
identifier conflicts with another optical signal (block 630--YES),
and/or if the selected wavelength is not tunable and routable at
either end (block 635--NO), process 600 may include determining
whether a wavelength limit is reached (block 640). For example,
network management device 210 may determine whether the wavelength
limit is reached. The wavelength limit may refer to a quantity of
wavelengths, w, that may be considered for assignment to the
optical signal. For example, network management device 210 may
determine whether there are no remaining wavelengths, of the set of
wavelengths, which have been selected for assignment to the optical
signal.
[0079] As further shown in FIG. 6B, if the wavelength limit is not
reached (block 640--NO), process 600 may include returning to block
625. For example, network management device 210 may select another
wavelength identifier, of the set of wavelength identifiers, to
assign to the optical signal. In some implementations, network
management device 210 may select the other wavelength identifier
based on a saturation degree, a degree of the vertex, a quantity of
unassigned neighbors, or the like.
[0080] As further shown in FIG. 6B, if the wavelength limit is
reached (block 640--YES), process 600 may include moving the
optical signal to another PIC (block 645). For example, network
management device 210 may move the optical signal to another PIC
associated with a particular ROADM 260. In some implementations,
network management device 210 may select another PIC, of a set of
other PICs associated with the particular ROADM 260, based on a
quantity of optical signals being transmitted by the other PIC, a
quantity of wavelengths assigned to optical signals being
transmitted by the other PIC, or the like. In some implementations,
network management device 210 may move the optical signal to
another transmitting PIC associated with the same or a different
ROADM 260, another receiving PIC associated with the same or a
different ROADM 260, or the like. Additionally, or alternatively,
network management device 210 may move the optical signal to
another transmitting PIC associated with a first ROADM 260 and to
another receiving PIC associated with a second ROADM 260. In some
implementations, network management device 210 may iteratively move
the optical signal to one or more other PICs until network
management device 210 is able to determine a wavelength identifier
that does not conflict with another optical signal and is able to
determine that the selected wavelength is tunable and routable at
either end.
[0081] As further shown in FIG. 6B, process 600 may include
updating the wavelength identifier graph based on moving the
optical signal to the other PIC (block 650) and returning to block
620. For example, network management device 210 may update the
wavelength identifier graph based on moving the optical signal to
the other PIC. In some implementations, network management device
210 may alter a set of edges and a set of vertices when updating
the wavelength identifier graph. For example, network management
device 210 may remove a vertex associated with the optical signal
and may remove edges associated with the vertex. In some
implementations, network management device 210 may remove one or
more other edges of the wavelength identifier graph and/or add one
or more other edges to the wavelength identifier graph. In some
implementations, network management device 210 may activate another
PIC when moving the optical signal to the other PIC. For example,
when network management device 210 is unsuccessful with wavelength
assignment for all active PICs of ROADM 260, network management
device 210 may activate another PIC of ROADM 260 for the optical
signal.
[0082] In some implementations, network management device 210 may
generate another wavelength identifier graph. For example, network
management device 210 may determine another logical topology for
the optical signals based on moving the optical signal to the other
PIC and may generate another wavelength identifier graph based on
the other logical topology for the optical signals. In some
implementations, network management device 210 may generate another
wavelength identifier graph for the other PIC. For example, network
management device 210 may generate another wavelength identifier
graph associated with the other PIC to perform wavelength
assignment for the other PIC based on moving the optical signal to
the other PIC. In some implementations, network management device
210 may select another optical signal, of the set of optical
signals, for wavelength assignment.
[0083] As further shown in FIG. 6B, if the selected wavelength is
tunable and routable at either end (block 635--YES), process 600
may include assigning the wavelength identifier to the optical
signal (block 655). For example, network management device 210 may
assign the wavelength corresponding to the wavelength identifier to
the optical signal. In some implementations, network management
device 210 may instruct ROADM 260 to transmit and/or receive the
optical signal at the wavelength corresponding to the wavelength
identifier. For example, network management device 210 may cause a
laser associated with a particular PIC of ROADM 260 to be tuned to
the wavelength that corresponds to the wavelength identifier when
transmitting/receiving the optical signal. Additionally, or
alternatively, network management device 210 may wait until
wavelength assignment is complete before causing the laser
associated with the particular PIC of ROADM 260 to be tuned to the
wavelength.
[0084] As further shown in FIG. 6B, process 600 may include
determining whether there are any optical signals without an
assigned wavelength identifier (block 660). For example, network
management device 210 may determine whether another optical signal,
of the set of optical signals, lacks an assigned wavelength
identifier corresponding to a wavelength.
[0085] As further shown in FIG. 6B, if there is another optical
signal without an assigned wavelength identifier (block 660--YES),
process 600 may include returning to block 620. For example,
network management device 210 may select the other optical signal
for wavelength assignment, as discussed herein with regard to block
620. In some implementations, network management device 210 may
select the other optical signal, from a set of other optical
signals that have not been assigned a wavelength identifier
corresponding to a wavelength, based on a criteria, such as a
saturation degree, a degree of a vertex associated with the other
optical signal, a quantity of unassigned neighbors, or the
like.
[0086] As further shown in FIG. 6B, if there are not any optical
signals without an assigned wavelength identifier (block 660--NO),
process 600 may include determining wavelength assignment is
complete (block 665). For example, network management device 210
may determine that wavelength assignment is complete and may notify
a set of ROADMs 260 associated with transmitting/routing/receiving
the set of optical signals that the set of optical signals may be
transmitted/routed/received using the set of assigned wavelengths.
In some implementations, network management device 210 may monitor
optical network 220 to determine whether wavelength assignment
should be performed again based on an alteration to optical network
220. For example, network management device 210 may receive
information from network devices 230 of optical network 220
indicating the alteration to optical network 220, such as an
optical signal being added, an optical signal being dropped, a
quantity of network traffic being altered, or the like. In this
case, network management device 210 may determine whether a
topology (e.g., a logical topology, a fiber topology, or the like)
has changed, and may perform wavelength assignment again based on
determining that the topology has changed.
[0087] Although FIGS. 6A and 6B shows example blocks of process
600, in some implementations, process 600 may include additional
blocks, fewer blocks, different blocks, or differently arranged
blocks than those depicted in FIGS. 6A and 6B. Additionally, or
alternatively, two or more of the blocks of process 600 may be
performed in parallel.
[0088] FIG. 7 is a diagram of example components of a device 700.
Device 700 may correspond to network management device 210, and/or
another device described herein. In some implementations, network
management device 210, and/or another device described herein may
include one or more devices 700 and/or one or more components of
device 700. As shown in FIG. 7, device 700 may include a bus 710, a
processor 720, a memory 730, a storage component 740, an input
component 750, an output component 760, and a communication
interface 770.
[0089] Bus 710 may include a component that permits communication
among the components of device 700. Processor 720 is implemented in
hardware, firmware, or a combination of hardware and software.
Processor 720 may include a processor (e.g., a central processing
unit (CPU), a graphics processing unit (GPU), an accelerated
processing unit (APU), etc.), a microprocessor, and/or any
processing component (e.g., a field-programmable gate array (FPGA),
an application-specific integrated circuit (ASIC), etc.) that
interprets and/or executes instructions. Memory 730 may include a
random access memory (RAM), a read only memory (ROM), and/or
another type of dynamic or static storage device (e.g., a flash
memory, a magnetic memory, an optical memory, etc.) that stores
information and/or instructions for use by processor 720.
[0090] Storage component 740 may store information and/or software
related to the operation and use of device 700. For example,
storage component 740 may include a hard disk (e.g., a magnetic
disk, an optical disk, a magneto-optic disk, a solid state disk,
etc.), a compact disc (CD), a digital versatile disc (DVD), a
floppy disk, a cartridge, a magnetic tape, and/or another type of
computer-readable medium, along with a corresponding drive.
[0091] Input component 750 may include a component that permits
device 700 to receive information, such as via user input (e.g., a
touch screen display, a keyboard, a keypad, a mouse, a button, a
switch, a microphone, etc.). Additionally, or alternatively, input
component 750 may include a sensor for sensing information (e.g., a
global positioning system (GPS) component, an accelerometer, a
gyroscope, an actuator, etc.). Output component 760 may include a
component that provides output information from device 700 (e.g., a
display, a speaker, one or more light-emitting diodes (LEDs),
etc.).
[0092] Communication interface 770 may include a transceiver-like
component (e.g., a transceiver, a separate receiver and
transmitter, etc.) that enables device 700 to communicate with
other devices, such as via a wired connection, a wireless
connection, or a combination of wired and wireless connections.
Communication interface 770 may permit device 700 to receive
information from another device and/or provide information to
another device. For example, communication interface 770 may
include an Ethernet interface, an optical interface, a coaxial
interface, an infrared interface, a radio frequency (RF) interface,
a universal serial bus (USB) interface, a Wi-Fi interface, a
cellular network interface, or the like.
[0093] Device 700 may perform one or more processes described
herein. Device 700 may perform these processes in response to
processor 720 executing software instructions stored by a
computer-readable medium, such as memory 730 and/or storage
component 740. A computer-readable medium is defined herein as a
non-transitory memory device. A memory device includes memory space
within a single physical storage device or memory space spread
across multiple physical storage devices.
[0094] Software instructions may be read into memory 730 and/or
storage component 740 from another computer-readable medium or from
another device via communication interface 770. When executed,
software instructions stored in memory 730 and/or storage component
740 may cause processor 720 to perform one or more processes
described herein. Additionally, or alternatively, hardwired
circuitry may be used in place of or in combination with software
instructions to perform one or more processes described herein.
Thus, implementations described herein are not limited to any
specific combination of hardware circuitry and software.
[0095] The number and arrangement of components shown in FIG. 7 are
provided as an example. In practice, device 700 may include
additional components, fewer components, different components, or
differently arranged components than those shown in FIG. 7.
Additionally, or alternatively, a set of components (e.g., one or
more components) of device 700 may perform one or more functions
described as being performed by another set of components of device
700.
[0096] In this way, a ROADM may output optical signals within a
super-channel in multiple directions and a network management
device, associated with the ROADM, may efficiently assign optical
signal wavelengths based on a set of criteria that includes
avoiding a lightpath conflict.
[0097] The foregoing disclosure provides illustration and
description, but is not intended to be exhaustive or to limit the
implementations to the precise form disclosed. Modifications and
variations are possible in light of the above disclosure or may be
acquired from practice of the implementations.
[0098] As used herein, the term component is intended to be broadly
construed as hardware, firmware, or a combination of hardware and
software.
[0099] It will be apparent that systems and/or methods, described
herein, may be implemented in different forms of hardware,
firmware, or a combination of hardware and software. The actual
specialized control hardware or software code used to implement
these systems and/or methods is not limiting of the
implementations. Thus, the operation and behavior of the systems
and/or methods were described herein without reference to specific
software code--it being understood that software and hardware can
be designed to implement the systems and/or methods based on the
description herein.
[0100] Even though particular combinations of features are recited
in the claims and/or disclosed in the specification, these
combinations are not intended to limit the disclosure of possible
implementations. In fact, many of these features may be combined in
ways not specifically recited in the claims and/or disclosed in the
specification. Although each dependent claim listed below may
directly depend on only one claim, the disclosure of possible
implementations includes each dependent claim in combination with
every other claim in the claim set.
[0101] No element, act, or instruction used herein should be
construed as critical or essential unless explicitly described as
such. Also, as used herein, the articles "a" and "an" are intended
to include one or more items, and may be used interchangeably with
"one or more." Furthermore, as used herein, the term "set" is
intended to include one or more items (e.g., related items,
unrelated items, a combination of related items and unrelated
items, or the like), and may be used interchangeably with "one or
more." Where only one item is intended, the term "one" or similar
language is used. Also, as used herein, the terms "has," "have,"
"having," or the like are intended to be open-ended terms. Further,
the phrase "based on" is intended to mean "based, at least in part,
on" unless explicitly stated otherwise.
* * * * *